220 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 150 



LEUCOPTERNIS SEMIPLUMBEA Lawrence: Semiplumbeous Hawk; 

 Gavilan Cenizo 



Leticoptemis semiplumbeus Lawrence, Ann. Lye. Nat. Hist. New York, vol. 7, 

 Jan. 1861, p. 288. (Along the Panama Railroad, Caribbean slope, Canal Zone, 

 Panama.) 



A small gray species, with black, white-banded tail, and white 

 lower surface ; bill and feet orange. 



Description. — Length 310 to 350 mm. Adult, upper tail coverts 

 and tail black, latter with a white subterminal band ; in some specimens 

 a second more or less complete white band below the upper tail 

 coverts ; rest of upper surface dark gray, usually darker on the head, 

 with indistinct shaft lines of black ; below white, including the under 

 wing coverts; a few narrow shaft lines of grayish black on throat 

 and foreneck; tips of primaries and secondaries on under surface 

 light gray, barred and tipped with blackish gray; rest of under wing 

 white. 



Juvenile, breast and sides of throat with narrow dark gray shaft 

 stripes. 



A male taken near Chimin on February 23, 1950, had the iris bright 

 yellow; cere, side of premaxilla, gape, and base of mandible to 

 symphysis deep orange; sides of maxilla at base and mandible in 

 front of symphysis for one-third its length dull honey yellow ; rest 

 of bill dark neutral gray; tarsus deep orange; claws dark neutral 

 gray. Another male shot at Boca de Paya, Darien, on March 8, 

 1959, was similar in bill, eye, and tarsus, and in addition I noted 

 that the edge of the eyelids, lores, and the bare skin above the eye 

 were orange-yellow and that the skin beneath the feathers on the 

 underside of the wing (including the patagium), foreneck, abdomen, 

 and knee was dull yellow. 



There is a prominent powder down patch across the thigh. 



Measurements (from Friedmann, U, S. Nat. Mus. Bull. 50, pt. 10, 

 1950, p. 384).— Males (7 specimens), wing 165-184 (179), tail 127- 

 137 (132.4), culmen from cere 18-20 (19.2), tarsus 55-64 (60.1) mm. 



Females (14 specimens), wing 183-202 (195.2), tail 126-148 

 (135.7), culmen from cere 18-21 (20), tarsus 57-66 (61.6) mm. 



Resident. Local in forested areas in the tropical zone; recorded 

 on the Pacific slope from Veraguas eastward through Darien, and on 

 the Caribbean side from Bocas del Toro east through the Comarca 

 de San Bias (Perme, Armila, Puerto Obaldia), including the Chagres 

 Valley (Quebrada Peluca on the Rio Boqueron). 



There are no reports from the Azuero Peninsula, and the only 

 one from \'eraguas is of a specimen without locality collected by Arce 



